Abstract

Domestic ruminants select a mixed diet when grazing heterogeneous pastures. Adjacent monocultures allow diet preference to be evaluated without certain constraints that could influence diet selection; however, few forage species have been evaluated. Adjacent monocultures of tall fescue (Festuca arundinacea Schreb.) and alfalfa (Medicago sativa L. ssp. sativa) were used to test the theories that selection of mixed diets is influenced by a plant's “novelty,” and that regardless of forage species, cattle will have a partial preference for legumes over grasses. Cattle without previous experience eating alfalfa spent 78% of total grazing time eating alfalfa, whereas after having experience grazing alfalfa they spent less (P = 0.04) time grazing alfalfa (72%). Overall, proportion of the day spent grazing was less (P = 0.001) when alfalfa was novel (40%) than when steers were experienced with both forages (46%). Proportion of the day spent idling was greater (P < 0.001) when alfalfa was novel (35%) than when both forages were familiar (26%). The proportion of grazing time in alfalfa was greater (P = 0.02) in the afternoon (76.8%) than in the morning (72.1%), differing from previous studies that reported a decline in legume preference over the day with an increased grass preference in the afternoon. Application of adjacent monocultures in production systems would benefit from additional research on performance of cattle grazing in this paddock arrangement.

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